Carpal Tunnel Syndrome (CTS)

By Richard H. Adler

April 10, 2010

Carpal Tunnel Syndrome (CTS) occurs when tendons or ligaments in the wrist become enlarged from inflammation. While most commonly seen following repetitive use of the hands and arms, Carpal Tunnel Syndrome also occurs as a consequence of a traumatic injury event like a car collision.

The carpal “tunnel” is formed by a semi-circle of carpal bones on three sides and the transverse carpal ligament on the fourth side. This ligament is not designed to stretch. The carpal tunnel is a defined space that cannot enlarge and there is only so much room in that opening. Through that opening pass the median nerve, nine tendons, and spongy tissue around the tendons called tenosynovium. When inflamation of the tendons and ligaments occupying the narrow carpal tunnel occurs, it “pinches” or places the median nerve under compression, impacting nerve conduction to the fingers and to the muscles at the base of the thumb.

A Carpal Tunnel Syndrome (CTS) injury is often sustained by the driver of a motor vehicle whose car has been hit from behind or head-on. The acceleration-deceleration forces in such a motor vehicle collision cause rapid and forceful hyper-extension of the wrist when gripping the steering wheel or when the hand is forcefully impacted on the dashboard. This stretches and stresses the structures within the carpal tunnel. The mechanism of injury is likely a direct blow or compressive force, or combination of both, causing the wrist to hyper-extend and the median nerve to stretch. This in turn causes a chronic cycle of inflammation and resulting pressure around the median nerve.

Symptoms of Carpal Tunnel Syndrome may include numbness which is periodic or constant in one or both hands. The subjective complaints are of numbness which often include the entire hand, even though median neuropathy at the carpal tunnel affects only the thumb, index and middle fingers. Symptoms may also include burning and/or tingling numbness in the fingers, especially within the thumb and the index and middle fingers. Decreased grip strength may make it difficult to form a fist, grasp small objects (causing the dropping of items) or perform other manual tasks.

A number of different activities may precipitate the symptoms including driving, writing, typing, sewing, holding a book, magazine or newspaper. Very often the patient reports first experiencing the symptoms at night when the affected hand is at rest, because the constricting action of hand use does not occur to “pump-away” the accumulation of fluid in the tissues of the wrist and hand. In chronic or untreated cases, the muscles at the base of the thumb may actually atrophy and waste away.

Treatment and interventions to mitigate or resolve Carpal Tunnel Syndrome may include work place training in hand and work postures and work place ergonomic changes which may reduce aggravation of the traumatically injured median nerve during repetitive work motions. Other treatment regimens may include chiropractic manipulation and physical therapies; the fitting and use of wrist splints to reduce compression of the carpal tunnel through flexing and extension of the wrist, as well as to provide support; and non-steroidal anti-inflammatories (aspirin, acetophenimen, ibubrophen, etc.) to reduce the inflammatory process around the structures within the carpal tunnel.

Ultimately, surgical release to effect an enlargement of the carpal tunnel may be required to eliminate pressure upon the median nerve on a more permanent basis altogether. Failure to address traumatically induced Carpal Tunnel Syndrome may result in permanent nerve injury.

Very often diagnosis of Carpal Tunnel Syndrome caused by a traumatic personal injury is delayed because symptoms do not develop for weeks or months post collision and the emergency room record does not indicate a hand injury. 1 One study suggests Carpal Tunnel Syndrome injuries may occur in as many as 22% of all car collisions which cause personal injuries. 2 Diagnosis of a Carpal Tunnel Syndrome injury may be complicated by a traction injury to the ulnar nerve within the post-condylar groove from hyper-flexion of the elbow. 3 This then creates circumstances calling for a difficult differential diagnosis by the physician.

Trauma to both sites, the wrist and elbow, from an automobile collision or other injury incident such as a trip and fall or bicycle incident may call for the diagnosis of “double crush syndrome” after appropriate clinical and diagnostic evaluation. Because of the frequent delay in onset of symptoms and delay in diagnosis of Carpal Tunnel Syndrome following a car collision or other traumatic incident, causation is often mistakenly attributed to work or recreational activities that involve repetitive hand or arm movements rather than to the motor vehicle collision or other trauma. Careful history taking by the clinician regarding the similarity of activities before the collision which did not precipitate symptoms, and the bio-mechanical events of the car collision or other injury incident are recommended to limit the potential for a mistaken attribution of cause to events other than the traumatic incident.

Experienced personal injury attorneys can play a constructive and useful role early on in any Carpal Tunnel Syndrome type case where significant medical legal issues impacting the injured personals ability to recover will be present. They can assist in obtaining the pre-trauma medical history to rule out any pre-existing condition and investigating the biomechanical and pathophysiological factors of the motor vehicle collision as it relates to arm, wrist, and hand trauma.

Legal consultations with the personal injury recovery professionals at Adler Giersch PS through their offices in Seattle, Bellevue, Everett and Kent are without charge or expense to your patient.